On 30 August 2012, Yesil signed for the Reds from Bayer Leverkusen for an undisclosed fee- reported to be as little as £1,000,000. A highly-rated forward, Yesil will initially be based with the Under 21 squad for the 2012-13 season. Yesil credited the kind words spoken to him about Liverpool by Leverkusen manager and former Kop idol Sami Hyypia with helping him agree to the move. Yesil made his Under 21s debut on 14 September 2012, playing the first 58 minutes of the side's 4-1 win over their Chelsea counterparts. He made his senior debut on the 26 September 2012 in a League Cup 3rd round victory against West Bromwich Albion, playing the first 81 minutes of the match before being substituted for Jerome Sinclair. On 31 October 2012, Yesil made his second appearance for Liverpool, playing 45 minutes in the 3-1 defeat to Swansea.

On 7 December 2012, Yesil netted his first goal in a Liverpool shirt. The goal came in an Under 21s match against Crystal Palace, with Yesil impressively lobbing the Palace 'keeper after being put through on goal by Craig Roddan's high ball over the defence. Yesil netted four goals in his first five games with the U21s and looked to be on course to have a very impressive campaign, however his season was cut short by an anterior cruciate ligament tear and he was unable to make another appearance in the campaign.

Yesil returned to action on 7 October 2013 in the U21's 5-0 victory over Tottenham. Yesil came on for the final 20 minutes, and almost scored after being put through one-on-one with the 'keeper, but was denied by the post. Yesil made three further appearances for the U21s, netting one goal as he continued his recovery, however in January 2014, it was reported that he had suffered a second anterior cruciate ligament tear.

On 31 August 2015, Yesil was sent out on loan to FC Luzern for the 2015-16 season. After an unsuccessful loan, it was confirmed on 10 June 2016 that Yesil had been released from the club after his contract expired.

The German made 2 appearances for the club, but none after his first season.